Sherlock Holmes said, “I never guess. It is a shocking habit — destructive to the logical faculty.” But most of us guess all the time. When something breaks, our frontal cortex lights up with dozens of ideas of what might be wrong and how to fix it.

Guessing is human nature, but great problem-solvers know it doesn’t work, and resist the temptation. Instead, they study what’s wrong and why it happened. They carefully investigate the pattern of failure and invest time in discovering the root cause, where the solutions always are.

If you and your team really want to solve a problem, get rid of the guesswork. Need convincing? Here are 7 firm reasons to stop guessing and start problem-solving:

1. Just because we guess doesn’t make it right.

Guessing has been a natural brain function since our cave-dwelling days. We guessed to survive: Which tool will stop the charging sabre-toothed tiger? We’re out of the caves, but the habit’s hardwired. Through nature and nurture, it’s become a foundation of our problem-solving skill set. Teachers praise students for guessing: even if it’s wrong, good try! Businesses default to guessing to appease the need for fast action. It looks heroic to roll up our sleeves and dive in, but we don’t know what we’re doing.

2. Guessing wastes time.

Spending hours testing different guesses is expensive. I was at a factory where a machine broke down, halting production. A mechanic spent 8 hours “troubleshooting,” changing half a dozen parts until he finally found the broken one. “First I changed out this part, but that didn’t fix it, then this other part, but that didn’t work …” and so on. If he’d investigated the root cause, he could have gotten production back online faster. His approach assumed that 6 parts of one machine were equally likely to fail at the same time, which is highly unlikely. He didn’t problem-solve, he solution-guessed.

3. If guessing works, it’s only because the problem’s easy.

Guessing only helps on problems with potentially two or three root causes. In this case it’s easy, cheap, and fast enough to test each one. A lamp goes out? Try changing the light bulb. But what if the lamp keeps going out even after the light bulb is changed repeatedly, and the breaker’s flipped? Now you’re facing a more complicated problem with possibly a dozen potential root causes. Often, problems of moderate difficulty entail some 50 potential root causes. Every guess takes time and resources, and you’ll have no way of knowing you’ve guessed right until you’ve completed testing it.

4. With hard problems, guessing can make things worse.

Hard problems might have hundreds or thousands of potential causes, and often, the actual root cause is obscure or hidden. A software program does 98% of everything right but won’t finish the task. One tiny section somewhere along miles of piping corrodes. You are unlikely to be able to guess these causes, and it wastes a lot of time. Trying to implement some of these guesses eats up huge amounts of resources. Months later, you have nothing to show for it. And all the random changes you have made may have created new problems.

5. Guessing is a huge distraction for a team.

Tasked with solving a problem, teams often mistakenly launch into a brainstorming session. Brainstorming has its place where creativity is required, but solving hard problems is not one of them. Dressed up in an elaborate “process” for prioritizing guesses, such as a fishbone diagram, it’s still just group-guessing — adding further complications, like groupthink and politics, that drive managers nuts. And people tend to get attached to their ideas, dig in, and play power games, so the guess tested first is the one made by the most powerful person in the room. If the team brainstorms dozens of “possible root causes,” all must be tested. One diplomatic solution: get it out of everyone’s system by writing all the guesses down. It’s fun to play “who guessed right” after the fact. But you haven’t wasted endless time and resources belaboring through the hit-and-miss.

6. Guessing doesn’t teach you anything.

Even if a guess eventually works, you’ve spent lots of time on guesses that didn’t, and you probably won’t have any deeper understanding of the problem than you did in the first place. Be aware that any time you “come up with” many possible causes to check, you are guessing. If someone gives you a list of 10 “potential” root causes, they don’t know what’s happening. If your team comes up with 200 potential root causes, no onedoes. That’s far too many ideas to explore before you run out of time, resources, and energy, and you still won’t know what’s happening. Worse: when a team doesn’t understand a problem or the system behind it, odds are the true root cause isn’t even on that list.

7. Guessing has side effects.

Say you got lucky: You guessed a solution and implemented it effectively. Unfortunately, this rare victory has some bad side effects. First, you’ve reinforced the habit, and fooled yourself into thinking it’s a good strategy and will work again, making it harder to break in the future. Whether or not guessing works, it’s easy, and we find comfort in that. Second, you haven’t developed any deeper understanding of the problem. Instead of spending time building knowledge (since future problems will inevitably pop up), you’ve spent your time guessing and checking. Next time it happens, you’re back to square one.

Third, you’re not becoming a better problem-solver. You rob yourself and your team of critical skills development. When you get to truly hard problems, you’ll need all the skills you can get. If you don’t practice using the right behaviors and methods to solve moderate problems, you’ll never master them. You’re going to get shellacked when you try to tackle the hard problems.

I’ve worked with bright talent, fresh out of universities like MIT and Cornell, brilliant young people with technical degrees and a deep scientific foundation. They’ve synthesized complex chemicals and built robots, but facing their first hard practical problem, they all resort to guessing first. It’s a natural compulsion, even for them. They’re trained to solve problems, so realize quickly that guessing inhibits their progress. Once they set guesswork aside, they’re tackling hard problems with panache.

Remember, your brain is going to guess. When it happens, recognize it for what it is — a primitive survival instinct. Then, let go of the guess — and get to work.